Causes

Blood clots form when certain parts of your blood thicken, forming a semisolid mass. This process may be triggered by an injury or it can sometimes occur inside blood vessels that don't have an obvious injury.

Once these clots form, they can travel to other parts of your body, causing harm. Factors and conditions that can cause troublesome blood clots, as well as serious conditions that are associated with blood clots, include:

• Antiphospholipid syndrome
• Arteriosclerosis / atherosclerosis
• Certain medications, such as oral contraceptives and hormone therapy drugs
• Coronavirus disease 2019 (COVID-19)
• Deep vein thrombosis (DVT) (DVT)
• Factor V Leiden
• Family history of blood clots
• Heart arrhythmia (heart rhythm problems)
• Heart attack
• Heart failure
• Obesity
• Peripheral artery disease (PAD)
• Polycythemia vera
• Pregnancy
• Prolonged sitting or bed rest
• Pulmonary embolism (blood clot in an artery in the lung)
• Smoking
• Stroke
• Surgery